Apparatus for the production of high-bulk yarn



June 23, 1959 VANDAMME ETAL I 2,891,375

APPARATUS FOR THE PRODUCTION OF HIGH-BULK YARN Filed Jan. 2, 1957 eYW ATTORNEY United States Patent- APPARATUS FOR THE' PRODUCTION OF HIGH-BULK YARN Louis Vandamme and Louis Rouyer, Saulce, France, assignors to Moulinage et Retarderie de Chavanoz, Chavanoz (Isere) France, a corporation of France Application January 2, 1957, Serial No. 632,141

Claims priority, application France January 6, 1956 3 Claims. (Cl. 5734) This invention relates to apparatus for producing] bulked yarn by imparting thereto and setting a false twist.

Manufacture of bulked yarns in synthetic textiles, for example of polyamide, has formed the subject of a large number of patents. One of the processes employed for this purpose comprises the application of a false twist which is immediately set.

In Patent No. 2,741,893 of April 17, 1956, there has been described process and apparatus for obtaining bulked yarn with the application of a false twist, in which the said false twist is set by virtue of the fact that it can advance freely in the yarn towards a thermal setting member which may be a hot water bath, a vaporizing tube, etc. According to the said patent, the yarn undergoes a heating and passes over a twist-arresting member and thereafter immediately enters the member which imparts the false twist.

United States Patent No. 2,761,272 of September 4, 1956 describes a modification in which the heating of the yarn is effected by prolonged contact with a heated curved surface, notably by means of an internal circulation of hot fluid. Applicants application Serial No. 534,945, filed September 19, 1955, now Patent No. ,780,047, describes another modification in which the heating element consists of an electric resistor in the form of a blade of U-section, in which the yarn is also heated by contact.

An object of the present invention is to provide a further improvement in which the heating element is a metal tube of small diameter which constitutes an electric resistor.

Other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

The invention will be better understood by referring to the following description taken in connection with the accompanying drawing in which the figure is a diagrammatic view of one embodiment of the apparatus embodying the present invention.

Referring to the drawing, the filament 1 from the winding 2 passes through a guide 3 and thence passes through a tube 5 which in the form shown is curved so that the filament contacts the surface of the tube as it is fed therethrough. In some instances however the tube 5 may be made straight instead of curved and the filament be caused to contact the side of the tube by suitable guide means. The tube 5 is provided with terminals 6 which are connected to a suitable source of electric current for heating the tube by its resistance effect.

The said tube 5 may be made of a metal known for its high resistance properties, for example, of nickelchrome alloy or of metals or alloys of lower resistance. The applied voltage is preferably low. In a bank of tubes the adjacent tubes may be connected in parallel or in a series.

The resistor tube 5 is thermally insulated by enclos- 2,891,375 Patented June 23, 1959 ing it ina large tube,10', for. example;severalcentimeters in. diameter, which is, internally linedbyan insulating, material 11, for example, vermiculite, which fills the entire space between 'the inne'r' "wall of thelarge' tube 10 and the surface ,ofrthere sis tor tube ,5. The ends of the large tube 19" are" closed discs'fl, for exam le of plastic material, with an orifice 13"of "a 'size for the" pas sage of the tube 5.

The filament after passing through the tube 5 is fed through a false twister 15 which is rotated by suitable means indicated as a belt 16 and is adapted to produce a twist in the filament which feeds back along the filament toward the heating tube 5 until it is arrested by contact of the filament with the surface of such tube. The temperature of the tube 5 is adapted to heat the filament for setting the false twist therein. Finally, the filament 1 passes through the guide 17 and is then wound onto a spool 18. The external insulation of the tube is readily applied and maintained.

The principal advantage of the resistor-type heating tube is that it is easier to produce with uniform resistance properties than the U-blade, which is a tubular segment and the fact that the convection radiation within the said tube, which appears to play an important part in the heating of the yarns continuously travelling through the tube, is efiiciently utilized.

For all these reasons, the output of the electric heating is clearly improved and the heat losses are reduced to a minimum.

The internal diameter of the heating tube 5 may vary, and may be, for example, of the order of several millimeters. These tubes are individually calibrated and are preferably arranged in series, for example, for a section of a machine or for one frame or bank.

Under these conditions the temperature Within the tube 5 may be adjusted to with :1" C. at most and even to within :05 C. for a group of tubes connected in series.

The use of the heating tube 5 furthermore permits ready positioning of the yarn by applying suction on one end of the tube. Individual starting of each tube may be envisaged or a group may be threaded by means of a suction device comprising a number of nozzles, which may be placed at the outlet from the group of tubes.

It will be understood that the invention is in no way limited to the embodiments referred to by way of example.

What is claimed is:

1. Apparatus for setting a false twist in synthetic thermo-plastic filaments comprising a heater tube composed of a peripheral wall completely surrounding a heating zone and made from metal having electrical resistance characteristics, said tube being curved axially into arcuate shape, means passing an electric current through said heater tube for heating said tube due to its resistance, means feeding said filaments through said tube in contact with the inner arcuate surface thereof, and a false twisting device disposed to impart a false twist to the filaments emerging from said tube, whereby the twist feeds along said filaments into the tube and is set therein and is removed after the filaments pass the false twisting device.

2. Apparatus as set forth in claim 1 in which heat insulation is disposed around said tube.

3. Apparatus for setting a false twist in synthetic thermoplastic filaments comprising a heater tube composed of a peripheral wall completely surrounding a heating zone, said tube being curved axially into arcuate shape, means heating the walls of said tube, means feeding the filaments through said tube in contact with the References Cited in the file of this patent UNTIED STATES PATENTS 2,761,272 Vandamme et al. Sept. 4, 1956 10 Stoddard et 3.1. Aug. 20, 1957 Kingsburg et a1. Nov. 19, 1957 Kunzle Feb. 11, 1958 FOREIGN PATENTS France Oct. 13, 1954 

